Nirvana is the ultimate spiritual goal in Buddhism and marks the soteriological release from rebirths in saṃsāra. Nirvana is part of the Third Truth on "cessation of dukkha" in the Four Noble Truths, and the summum bonum destination of the Noble Eightfold Path...
C is the correct answer. Anytime a king or queen rules over a country, it is called a monarchy. But since there were manors below him and helped him make laws, it would be a constitutional monarchy.